Advent-of-Code/2024/3/main.cpp

75 lines
1.5 KiB
C++

#include <fstream>
#include <iostream>
#include <regex>
#include <set>
#include <string>
#include <vector>
int main()
{
const std::string filename = "data.txt";
std::ifstream ifs(filename);
if(!ifs.is_open())
{
std::cerr << "Missing " << filename << "." << std::endl;
return -1;
}
unsigned long total = 0;
unsigned long total_pt2 = 0;
bool multiplying = true;
for(std::string line; std::getline(ifs, line); )
{
if(line == "")
continue;
std::regex pattern("do\\(\\)|don't\\(\\)|mul\\((\\d+),(\\d+)\\)");
auto pattern_begin = std::sregex_iterator(line.begin(), line.end(), pattern);
auto pattern_end = std::sregex_iterator();
for (std::sregex_iterator i = pattern_begin; i != pattern_end; ++i)
{
std::string result = i->str();
if(i->str() == "do()")
multiplying = true;
else if(i->str() == "don't()")
multiplying = false;
else
{
std::smatch::iterator ip_it = i->begin();
std::vector<long> numbers;
for (std::advance(ip_it, 1);
ip_it != i->end();
advance(ip_it, 1))
{
std::string n = *ip_it;
try {
numbers.push_back(std::atoi(n.c_str()));
} catch(const std::exception &e) {
std::cout << "ERROR: " << e.what() << std::endl;
exit(-1);
}
}
long result = 1;
if(numbers.size())
{
for(auto n : numbers)
result *= n;
if(multiplying)
total_pt2 += result;
total += result;
}
}
}
}
std::cout << " Total: " << total << std::endl;
std::cout << "PT2 Total: " << total_pt2 << std::endl;
return 0;
}